Combustor and gas turbine

ABSTRACT

A combustor is equipped with first burners each adopted as a main burner circulating a primary air to generate an air-fuel mixture, second burners each adopted as the main burner circulating the primary air in a direction opposite to the first burners to generate another air-fuel mixture. A plurality of main burners are disposed at intervals in a circumferential direction, and the first burner and the second burner are disposed in a non-periodic arrangement pattern over an entire circumference in the circumferential direction.

TECHNICAL FIELD

The present disclosure relates to a combustor and a gas turbine.

Priority is claimed on Japanese Patent Application No. 2017-029640, filed Feb. 21, 2017, the content of which is incorporated herein by reference.

BACKGROUND ART

In some cases, a combustor of a gas turbine may be equipped with a plurality of main burners of the same shape arranged at equal intervals in a circumferential direction.

Patent Document 1 discloses a technique for forming a large-diameter short flame and a narrow flame by making a shape of a passage for mixing air in a slipstream of a fuel supply nozzle different to form a wide range of combustion flames and realize stability and low emission.

Patent Document 2 discloses a technique for imparting a circulating flow, which has directions opposite to circulating directions of swirlers adjacent to each other, to respective swirlers to reduce a shear occurring when outer edges of circulating flows caused by swirlers adjacent to each other merge and to reduce emissions of NOx and CO, in a combustor equipped with a plurality of swirlers having a circulation axis disposed parallel to a central axis in the circumferential direction.

CITATION LIST Patent Document

-   Patent Document 1: U.S. Pat. No. 6,931,853 -   Patent Document 2: U.S. Pat. No. 9,500,368

SUMMARY OF INVENTION Technical Problem

For example, when all the flames formed by a plurality of main burners disposed side by side in the circumferential direction have the same characteristics, the shape of the flame in the circumferential direction becomes uniform, and an axial length of the flame also becomes uniform in the circumferential direction.

The main burners described in Patent Document 2 are disposed such that the circulating directions of main burners adjacent to each other in the circumferential direction are opposite to each other. However, the flame formed by the main burners described in Patent Document 2 also becomes uniform in the circumferential direction.

When the flame is uniformly formed in the circumferential direction in this way, if a pressure fluctuation occurs in the main burners, the flame causes the same fluctuation in the circumferential direction. When the flames fluctuate in the same phase with each other, an amplitude of the fluctuation of the heat release rate in the combustor increases, and a combustion instability increases.

When a plurality of main burners having different external shapes are used to change the shape of the flame as in the combustor described in Patent Document 1, there is a problem of an increase in the manufacturing man-hours required for the main burners.

The present disclosure provides a combustor and a gas turbine in which the occurrence of combustion instability is able to be inhibited, while increase in the number of man-hours involved in manufacturing of the main burners is inhibited.

Solution to Problem

According to a first aspect of the present disclosure, a combustor is equipped with a plurality of first burners each adopted as a main burner circulating a primary air in one direction to generate an air-fuel mixture, and a plurality of second burner each adopted as the main burner circulating the primary air in the other direction opposite to the first burner to generate another air-fuel mixture, wherein the main burners are disposed at intervals in a circumferential direction of the combustor, and the first and second burners are disposed in a non-periodic arrangement pattern over an entire circumference in the circumferential direction.

Since the first and second burners, in which directions of circulating the primary air are opposite to each other, are disposed in a non-periodic arrangement pattern over an entire circumference in the circumferential direction, thereby it is possible to inhibit the flame becoming uniform in the circumferential direction. Therefore, it is not necessary to use main burners of a plurality of types having different outlines.

As a result, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burners.

According to a second aspect of the present disclosure, the first and second burners according to the first aspect may be disposed in an asymmetric arrangement pattern in the circumferential direction.

Since the first burners and the second burners are not disposed with rotational symmetry, it is possible to inhibit formation of a uniform flame in the circumferential direction.

According to a third aspect of the present disclosure, the first and second burners according to the first aspect may be disposed in an arrangement pattern in which a concentration center of heat release rate of all the plurality of main burners is shifted away from a central position in the circumferential direction.

Since the concentration center of the heat release rate of the flames due to main burners as an index is shifted away from the central position of the arrangement of the plurality of main burners, it is possible to suppress a formation of a uniform flame, by breaking a balance of the flame in the circumferential direction.

According to a fourth aspect of the present disclosure, the first and second burners according to the first aspect may be disposed in an arrangement pattern in which a magnitude of a composite vector obtained by combining each of unit vectors according to a direction of a radial flow occurring at a boundary between the first and second burners in the circumferential direction is equal to or greater than magnitudes of the unit vectors.

Since the arrangement pattern of the first and second burners in the circumferential direction is set as an arrangement pattern in which the magnitude of the composite vector is equal to or greater than the magnitude of the unit vectors, it is possible to suppress a formation of a uniform flame, by breaking a balance of the flame in the circumferential direction.

According to a fifth aspect of the present disclosure, in the combustor according to the first aspect, in a condition where the plurality of main burners disposed at intervals in the circumferential direction are divided in the circumferential direction into groups including one or some of the main burners adjacent to each other in the circumferential direction and each groups includes the same number of the main burners, an arrangement relationship between the first and second burners in at least one of the groups may be different from other groups.

With such a configuration, formation of a uniform flame in the circumferential direction can be suppressed.

According to a sixth aspect of the present disclosure, a gas turbine is equipped with the combustor according to any one of the first to fifth aspects.

With such a configuration, it is possible to reduce the instability of the operating state due to the combustion instability.

Advantageous Effects of Invention

According to the combustor and the gas turbine mentioned above, an occurrence of a combustion instability can be suppressed, while suppressing an increase in man-hour related to manufacturing of a main burner.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing a schematic configuration of a gas turbine according to a first embodiment of the present disclosure.

FIG. 2 is a view showing a schematic configuration of a combustor according to the first embodiment of the present disclosure.

FIG. 3 is a view showing an arrangement of main burners in the first embodiment of the present disclosure.

FIG. 4 is a view showing a circulating direction of the main burners in the first embodiment of the present disclosure.

FIG. 5 is a view showing a concentration center of heat release rate in the first embodiment of the present disclosure.

FIG. 6 is a view showing a composite vector in the first embodiment of the present disclosure.

FIG. 7 is a view corresponding to FIG. 4 in a second embodiment of the present disclosure.

FIG. 8 is a view corresponding to FIG. 4 in a third embodiment of the present disclosure.

FIG. 9 is a view corresponding to FIG. 4 in a fourth embodiment of the present disclosure.

FIG. 10 is a graph in which a vertical axis on a left side is a distance between the concentration center of the heat release rate and the center of the combustor, a vertical axis on a right side is a magnitude of a composite vector, and a horizontal axis is a case number.

DESCRIPTION OF EMBODIMENTS First Embodiment

Next, a combustor and a gas turbine according to a first embodiment of the present disclosure will be described on the basis of the drawings.

As shown in FIG. 1, the gas turbine 1 is equipped with a compressor 2, a combustor 3, and a turbine 4.

The compressor 2 compresses air A to generate compressed air. The combustor 3 burns fuel F in the compressed air generated by the compressor 2 to generate a high-temperature and high-pressure combustion gas. The turbine 4 is driven by the combustion gas generated by the combustor 3 and converts energy of the combustion gas into rotational energy.

The compressor 2 is equipped with a compressor rotor 6 and a compressor casing 7. Further, the turbine 4 is equipped with a turbine rotor 8 and a turbine casing 9.

The compressor rotor 6 and the turbine rotor 8 are disposed in series and rotate about a rotation axis Ar. The turbine rotor 8 and the compressor rotor 6 are integrally connected to each other. A gas turbine rotor 10 is configured by the compressor rotor 6 and the turbine rotor 8. For example, a rotor of a generator GEN is connected to the gas turbine rotor 10.

The compressor casing 7 covers the compressor rotor 6 and rotatably supports the compressor rotor 6. The turbine casing 9 covers the turbine rotor 8 and rotatably supports the turbine rotor 8. The compressor casing 7 and the turbine casing 9 are connected to each other. The gas turbine rotor 10 is configured by the compressor rotor 6 and the turbine rotor 8. The combustor 3 is fixed to the gas turbine casing 11.

As shown in FIG. 2, the combustor 3 is equipped with a combustion cylinder (or a transition piece) 13 and a fuel ejector 14A. The combustion cylinder 13 burns the fuel F therein. The combustion cylinder 13 sends the combustion gas obtained as a result of burning the fuel F to the turbine 4. The fuel ejector 14A jets the fuel F and the compressed air A into the combustion cylinder 13.

As shown in FIG. 3, the fuel ejector 14A is equipped with a pilot burner 15, a main burner 16, and a burner holding cylinder 17.

The pilot burner 15 is disposed on a combustor axis Ac to diffuse and burn the fuel. The pilot burner 15 is equipped with a pilot nozzle 18, a pilot burner cylinder 19, and a pilot swirler (not shown).

The pilot nozzle 18 is formed to extend in the axial direction Da about the combustor axis Ac. The pilot nozzle 18 has, for example, an injection hole 18 a for fuel injection at a downstream side end portion thereof.

The pilot burner cylinder 19 is equipped with a main body 21 and a cone portion 22. The main body 21 covers an outer periphery of the pilot nozzle 18. The cone portion 22 is disposed on a downstream side of the main body 21. The cone portion 22 is formed to gradually increase in diameter toward the downstream side.

The pilot swirler (not shown) is disposed to on an upstream side with respect to a position at which the injection holes 18 a of the pilot nozzle 18 are formed in an axial direction Da. The pilot swirler (not shown) circulates the compressed air (primary air) A flowing from the upstream side about the combustor axis Ac as a circulation center. A pilot swirler (not shown) extends radially inward from an inner peripheral surface of the main body 21 of the pilot burner cylinder 19. A plurality of pilot swirlers (not shown) are formed, for example, at intervals in the circumferential direction.

The compressed air A compressed by the compressor 2 flows into the pilot burner cylinder 19 of the pilot burner 15 from the upstream side. The fuel is injected from the injection holes 18 a of the pilot nozzle 18. The fuel is jetted from the pilot burner cylinder 19 toward the combustion cylinder 13 together with the compressed air A which has been circulated by a pilot swirler (not shown) and is diffused and burned in the combustion cylinder 13.

A plurality of main burners 16 are provided. The main burners 16 are disposed to surround the outer periphery of the pilot burner 15. The main burners 16 pre-mix and burn the fuel. The main burners 16 are disposed at intervals in the circumferential direction centering on the combustor axis Ac. More specifically, the main burners 16 are disposed at equal intervals in the circumferential direction centering on the combustor axis Ac.

The main burner 16 is equipped with a main nozzle 23, a main burner cylinder 24 and a main swirler 25.

The main nozzle 23 extends parallel to the combustor axis Ac. The main nozzles 23 have injection holes 23 a for fuel injection, for example, on the outer peripheral surface thereof.

The main burner cylinder 24 covers the outer periphery of the main nozzle 23. In the main burner cylinder 24 illustrated in FIG. 3, a portion disposed on an inner side in the radial direction centering on the combustor axis Ac also serves as a part of the pilot burner cylinder 19.

The main swirler 25 circulates the compressed air (primary air) A flowing from the upstream side with the main nozzle 23 as a circulation center. The main swirler 25 extends from the inner peripheral surface of the main burner cylinder 24 toward the main nozzle 23. The main swirler 25 is provided in each of the plurality of provided main burners 16. A plurality of main swirlers 25 are provided at intervals in the circumferential direction centering on the main nozzle 23, respectively.

The burner holding cylinder 17 holds the pilot burner 15 and the main burner 16 described above. More specifically, the burner holding cylinder 17 holds the pilot burner 15 and the main burner 16 such that the plurality of main burners 16 surround the outer periphery of the pilot burner 15.

The compressed air A compressed by the compressor 2 flows into the main burner cylinder 24 of the main burner 16 from the upstream side. The fuel F is injected from the injection holes 23 a of the main nozzle 23. The fuel F is mixed with the compressed air A which has been circulated by the main swirler 25. After the fuel F is injected into the compressed air A, the main swirler 25 may circulate the compressed air A containing the fuel F. The premixed gas in which the fuel and the compressed air A are mixed together is jetted toward the combustion cylinder 13, and is premixed and burned in the combustion cylinder 13.

As shown in FIG. 4, the fuel ejector 14 is equipped with a plurality of first burners 16A each adopted as the main burner 16 and a plurality of second burners 16B each adopted as the main burner 16, wherein the circulating direction of the compressed air due to the main swirler 25 of the first burner 16A is opposite to the circulating direction of the compressed air due to the main swirler 25 of the second burner 16B. The first burner 16A and the second burner 16B have the same configuration except that the circulating directions are opposite to each other. In FIG. 4, the pilot burner 15 is not shown. The main burners 16 used in this embodiment are only the two types of the first burner 16A and the second burner 16B.

In the first embodiment, the circulating direction of the compressed air in the first burner 16A is counterclockwise as viewed from the combustion cylinder 13 side. Also, the circulating direction of the compressed air in the second burner 16B is clockwise as viewed from the combustion cylinder 13 side. In the fuel ejector 14A of the first embodiment, five first burners 16A are disposed consecutively in the circumferential direction. In the fuel ejector 14A of the first embodiment, three second burners 16B are continuously disposed in the circumferential direction. The fuel ejector 14A shown in FIG. 4 shows a case in which eight main burners 16 are provided, but the number of main burners 16 may be greater than 1, and may be, for example, nine or more or seven or less. In FIG. 4, the positions of the eight main burners 16 in the circumferential direction are indicated by arrangement numbers “1” to “8”, respectively.

The first burners 16A and the second burners 16B are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction in the fuel ejector 14A. Here, the “periodical arrangement pattern” is a pattern of the arrangement order of the first burners 16A and the second burners 16B in which only the same pattern is repeated while rotating in the circumferential direction about the combustor axis Ac. As an example of a periodic case, it is possible to adopt a case in which the first burners 16A and the second burners 16B are alternately disposed in the circumferential direction, a case in which only the first burners 16A are disposed, or a case in which only the second burners 16B are disposed.

That is, as the arrangement pattern of the main burners 16 in the fuel ejector 14A according to the first embodiment, the pattern of the arrangement order of the first burners 16A and the second burners 16B which is not repeated only in the same pattern, while rotating in the circumferential direction about the combustor axis Ac is adopted.

The first burners 16A and the second burners 16B are disposed in a circumferentially asymmetric arrangement pattern centering on the combustor axis Ac in the fuel ejector 14A. The circumferentially asymmetric arrangement pattern means that the first burners 16A and the second burners 16B are not disposed in an order of so-called rotational symmetry. In the following description of the embodiment, although a concentration center of heat release rate and a composite vector are used as an example of an indication of the non-periodicity of the arrangement pattern of the first burners 16A and the second burners 16B, only one of the concentration center of the heat release rate and the composite vector may be used.

In the fuel ejector 14A, the first burners 16A and the second burners 16B are disposed in an arrangement pattern in which a concentration center g (see FIG. 5) of the heat release rate of all the plurality of main burners 16 is shifted away from the combustor axis Ac which is a central position in the circumferential direction. When all the main burners 16 are the first burners 16A in the circumferential direction centering on the combustor axis Ac, when all the main burners 16 are the second burners 16B in the circumferential direction centering on the combustor axis Ac, and when the first burners 16A and the second burners 16B are alternately disposed in the circumferential direction centering on the combustor axis Ac, the heat release rate are balanced over the entire circumference. Therefore, the concentration center g of the heat release rate substantially coincides with the combustor axis Ac.

In FIG. 5, “8-1”, “1-2”, “2-3”, “3-4”, “4-5”, “5-6” and “6-7” are positions corresponding to the arrangement numbers of the main burners 16 shown in FIG. 4 respectively. In an example, “8-1” indicates a position between the positions “1” and “8” of the main burner 16.

Three second burners 16B of the fuel ejector 14A of the first embodiment are disposed continuously in the circumferential direction. Five first burners 16A of the fuel ejector 14A are disposed continuously in the circumferential direction. Therefore, as shown in FIG. 5, the heat release rate in the fuel ejector 14A expands outward at the position “8-1” at which a deviation occurs in the circumferential direction. The deviation of the heat release rate is considered to be due to the direction of swirling at a boundary between first burners 16A and second burners 16B adjacent to each other in the circumferential direction. The concentration center g of the heat release rate in the fuel ejector 14A is shifted away from the combustor axis Ac outwards from the position “8-1.” Here, in FIG. 5, when the first burner 16A is provided on the entire circumference in the circumferential direction centering on the combustor axis Ac (a case 0 to be described later), the heat release rate becomes “1” over the entire circumference in the circumferential direction (indicated by a solid line in FIG. 5). In this case, the concentration center g of the heat release rate overlaps the combustor axis Ac. When the swirl directed to the outside is strong in the radial direction centering on the combustor axis Ac, the heat release rate is 1.5, and when the swirl directed inward in the radial direction is strong, the heat release rate is 0.5 (indicated by a broken line in FIG. 5).

The first burners 16A and the second burners 16B of the fuel ejector 14A are disposed in an arrangement pattern that is a composite vector equal to or greater than the magnitude of the unit vector. Here, the unit vector is a vector according to the direction of the radial flow generated at the boundary between the first burner 16A and the second burner 16B in the circumferential direction centering on the combustor axis Ac. The composite vector is a vector obtained by combining each of the unit vectors in the fuel ejector 14A.

That is, the first burners 16A and the second burners 16B are disposed in an arrangement pattern in which the magnitude of the composite vector obtained by combining the unit vectors according to the direction of the radial flow generated at the boundary between the first burner 16A and the second burner 16B in the circumferential direction centering on the combustor axis Ac is equal to or greater than the magnitude of the unit vector.

For example, when the circulating directions of the compressed airs in the main burners 16 adjacent to each other are the same, since the circulating flows act to cancel each other out at the boundary of the main burners 16 adjacent to each other, a radial flow is not substantially generated. In a case in which the circulating directions of the compressed airs in the main burners 16 adjacent to each other are opposite to each other, the circulating flow of the main burners 16 adjacent to each other is directed in the same direction in the radial direction at the boundary between the main burners 16 adjacent to each other. That is, at the boundary between the first burner 16A and the second burner 16B, there is a flow directed inward or outward in the radial direction centering on the combustor axis Ac. When the radial flow occurring at the boundary is represented by a unit vector of magnitude “1”, it is possible to draw a unit vector UA directed radially outward and a unit vector UB directed radially inward as shown in FIG. 4.

As shown in FIG. 6, assuming that the position of the combustor axis Ac is at the origin (0, 0) coordinates in the fuel injector 14A of the first embodiment, the unit vector UA leads from (0, 0) coordinates to (0, 1) coordinates. The unit vector UB leads from (−0.71, 0.71) coordinates to (0, 0) coordinates. The magnitude of the sum of the unit vectors UA, UB (hereinafter referred to as a composite vector SV) is about 1.8. That is, the magnitude of the composite vector SV of the unit vectors UA, UB is one or more.

In the fuel ejector 14A, for example, a plurality of main burners 16 disposed at intervals in the circumferential direction are divided in the circumferential direction into some groups, and are set to “groups” each including the plurality of main burners 16 adjacent to each other in the circumferential direction and each groups includes the same number of the main burners 16. In this case, in the fuel ejector 14A according to the first embodiment of the present disclosure, an arrangement order (an arrangement relationship) of the first burners 16A and the second burners 16B in at least one group is different from that of the other groups.

As shown in FIG. 4, in the fuel ejector 14A of the first embodiment, if the two main burners 16 adjacent to each other in the circumferential direction are set as one group, four groups can be set in the circumferential direction. In this case, when viewed in one direction (for example, clockwise) in the circumferential direction, it is possible to set a first group G1 including the two second burners 16B which are “8” and “7” in the arrangement number of the main burners 16, and a second group G2 including one second burner 16B and one first burner 16A of the arrangement numbers “6” and “5”. Furthermore, it is possible to set a third group G3 including only the two first burners 16A of “4” and “3” in the arrangement number of the main burner 16, and a fourth group G4 including only the two first burners 16A of the arrangement numbers “2” and “1”. The arrangement order of the first burners 16A and the second burners 16B of the first group G1 in the circumferential direction is different from that of for any of the second group G2 to the fourth group G4. The main burners 16 combined as a group are not limited to the above-described arrangement numbers. For example, by setting “7” as the circumferential start point in the arrangement numbers of the main burners 16, each group may be similarly constituted by the arrangement numbers “7” and “6”, “5” and “4”, “3” and “2”, “1” and “8” and the like.

Since the fuel ejector 14A of the first embodiment has eight main burners 16, numbers by which the plurality of main burners 16 can be equally divided in the circumferential direction are two or four. Although it is not shown, the arrangement order of the first burners 16A and the second burners 16B in each group is also different in the case of four, as in the case of two. Further, one group may include one main burner 16.

According to the first embodiment, the first burners 16A and the second burners 16B are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction centering on the combustor axis Ac.

Thus, the fuel ejector 14A can form a flame that is not uniform in the circumferential direction, without using a plurality of types of main burners having different outlines.

As a result, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burner 16.

Further, since the first burners 16A and the second burners 16B are not disposed in rotational symmetry, it is possible to suppress the flame from becoming uniform in the circumferential direction.

Furthermore, since the concentration center of the heat release rate of the flames due to main burners 16 as an index is shifted away from the combustor axis Ac which is a central position of the arrangement of the plurality of main burners 16, it is possible to suppress a formation of a uniform flame, by breaking a balance of the flame in the circumferential direction.

Further, since the arrangement pattern of the first burners 16A and the second burners 16B in the circumferential direction is an arrangement pattern in which the magnitude of the composite vector SV is set to be equal to or greater than the magnitude of the unit vector UA, it is possible to suppress a formation of a uniform flame, by breaking a balance of the flame in the circumferential direction.

Furthermore, in a condition where the plurality of main burners 16 disposed at intervals in the circumferential direction are divided in the circumferential direction into groups each including one or some of the main burners 16 adjacent to each other in the circumferential direction and each groups includes the same number of the main burners 16, an arrangement relationship between the first burners 16A and the second burners 16B in at least one group is different from that of the other groups. Therefore, the formation of a uniform flame in the circumferential direction can be suppressed.

Second Embodiment

A second embodiment of the present disclosure will be described on the basis of the drawings. In the second embodiment, the arrangement pattern of the main burners is changed with respect to the first embodiment described above. Therefore, parts the same as those of the first embodiment will be explained by being denoted by the same reference numerals, and repeated explanation thereof will not be provided.

As shown in FIG. 7, a fuel ejector 14B according to the second embodiment is equipped with a first burner 16A and a second burner 16B as a plurality of main burners 16, as in the fuel ejector 14A of the first embodiment described above. The first burner 16A and the second burner 16B have the same configuration except that the circulating direction of the compressed air in the first burner 16A is opposite to the circulating direction of the compressed air in the second burner 16B.

The six first burners 16A of the fuel ejector 14B in the second embodiment are disposed continuously in the circumferential direction. The two second burners 16B of the fuel ejector 14B are disposed continuously in the circumferential direction. The fuel ejector 14B shown in FIG. 7 shows a case in which eight main burners 16 are provided as in FIG. 4, but the number of main burners 16 may be greater than 1, and may be, for example, nine or more and seven or less.

Like the fuel ejector 14A, the first burners 16A and the second burners 16B are disposed in the fuel ejector 14B in a non-periodic arrangement pattern over the entire circumference in the circumferential direction.

In the fuel ejector 14B, the first burner 16A and the second burner 16B are further disposed in an asymmetric arrangement pattern (an arrangement pattern that is not rotationally symmetrical) in the circumferential direction centering on the combustor axis Ac.

The concentration center g of the heat release rate in the fuel ejector 14B is shifted away from the combustor axis Ac, as in the fuel ejector 14A of the first embodiment.

As in the fuel ejector 14A of the first embodiment, the main burners 16 (the first burners 16A, and the second burners 16B) of the fuel ejector 14B are disposed in an arrangement pattern in which the magnitude of the composite vector SV obtained by combining each of the unit vectors UA and UB according to the direction of the radial flow generated at the boundary between the first burner 16A and the second burner 16B in the circumferential direction is equal to or greater than the magnitude of the unit vector UA (or UB).

When the two main burners 16 adjacent to each other in the circumferential direction are set as one group, four groups can be set in the circumferential direction in the fuel ejector 14B. In this case, when viewed in one direction (for example, clockwise) in the circumferential direction, a first group G1 including the two second burners 16B and a second group G2 to fourth group G4 including the two first burners 16A can be set. The arrangement order of the first burners 16A and the second burners 16B of the first group G1 in the circumferential direction is different for any of the second group G2 to the fourth group G4. The fuel ejector 14B of the second embodiment also has eight main burners 16 as in the first embodiment. That is, the number which can equally divide the plurality of main burners 16 in the circumferential direction is two or four.

According to the second embodiment described above, as in the first embodiment, the first burners 16A and the second burners 16B are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction centering on the combustor axis Ac.

Thus, the fuel ejector 14B can form a flame that is not uniform in the circumferential direction, without using a plurality of types of main burners having different outlines.

As a result, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burner 16.

Further, since the first burners 16A and the second burners 16B are not disposed in rotational symmetry, it is possible to suppress the flame from becoming uniform in the circumferential direction.

Furthermore, the concentration center g of the heat release rate of the flame due to main burners 16 as an index is shifted away from the combustor axis Ac which is the central position of the arrangement of the plurality of main burners 16. Therefore, it is possible to suppress the flame from becoming uniform in the circumferential direction, by breaking a balance of the flame in the circumferential direction.

Further, the arrangement pattern of the first burners 16A and the second burners 16B in the circumferential direction is an arrangement pattern in which the magnitude of the composite vector SV is equal to or greater than the magnitude of the unit vector UA (or UB). Therefore, it is possible to suppress the flame from becoming uniform in the circumferential direction, by breaking a balance of the flame in the circumferential direction.

Furthermore, in a condition where the plurality of main burners 16 disposed at intervals in the circumferential direction are divided in the circumferential direction into groups each including one or some of the main burners 16 adjacent to each other in the circumferential direction and each groups includes the same number of the main burners 16, an arrangement relationship between the first burners 16A and the second burners 16B in at least one group is different from the other groups. Therefore, it is possible to suppress the flame from being uniformly formed in the circumferential direction.

Third Embodiment

A third embodiment of the present disclosure will be described on the basis of the drawings. As in the second embodiment, in the third embodiment, the arrangement pattern of the main burners is changed with respect to the first embodiment described above. Therefore, the same part as those of the first embodiment mentioned above will be explained by being denoted by the same reference numerals, and the repeated explanation will not be provided.

As shown in FIG. 8, a fuel ejector 14C in the third embodiment is equipped with first burners 16A and second burners 16B as a plurality of main burners 16, as in the fuel ejector 14A of the first embodiment described above. The first burners 16A and the second burners 16B have the same configuration except that the circulating direction of the compressed air in the first burner 16A is opposite to the circulating direction of the compressed air in the second burner 16B.

The four first burners 16A of the fuel ejector 14C in the third embodiment are disposed continuously in the circumferential direction. The four second burners 16B of the fuel ejector 14C are disposed continuously in the circumferential direction. The fuel ejector 14C shown in FIG. 8 shows a case in which eight main burners 16 are provided as in FIG. 4, but the number of main burners 16 may be greater than 1, and may be, for example, nine or more or seven or less.

The first burners 16A and the second burners 16B of the fuel ejector 14C are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction, as in the fuel ejector 14A.

Here, the arrangement pattern of the first burners 16A and the second burners 16B of the third embodiment seems to be a periodic arrangement pattern at first glance. However, the periodic arrangement pattern mentioned here means, for example, an arrangement pattern in which any arrangement pattern in the order of the first burners 16A and the second burners 16B or in the order of the second burners 16B and the first burners 16A in the circumferential direction appears twice or more during one round in the circumferential direction, in the arrangement pattern in which the first burners 16A and the second burners 16B are adjacent to each other in the circumferential direction.

The first burners 16A and the second burners 16B of the fuel ejector 14B are disposed in a circumferentially asymmetric arrangement pattern (an arrangement pattern that is not rotationally symmetrical) centering on the combustor axis Ac.

The concentration center g of the heat release rate in the fuel ejector 14B is shifted away from the combustor axis Ac, as in the fuel ejector 14A of the first embodiment.

Although it is not shown, in the fuel ejector 14C, the magnitude of the composite vector SV obtained by combining the unit vectors UA and UB according to the direction of the radial flow generated at the boundary between the first burners 16A and the second burners 16B in the circumferential direction is equal to or greater than the magnitude of the unit vector UA (or UB). That is, the main burners 16 (the first burners 16A, and the second burners 16B) of the fuel ejector 14C are disposed in an arrangement pattern that is a composite vector SV equal to or greater than the magnitude of the unit vector UA (or UB). The magnitude of the composite vector SV in the third embodiment is twice as large as that of the unit vector UA (or UB).

When the two main burners 16 adjacent to each other in the circumferential direction are set as one group, the four groups can be set in the circumferential direction in the fuel ejector 14B. In this case, when viewed in one direction (for example, clockwise) in the circumferential direction, it is possible to set a first group G1 including one first burner 16A and one second burner 16B in which the arrangement position of the main burners 16 is “1” and “8”, a second group G2 including the two first burners 16A, a third group G3 including one second burner 16B and one first burner 16A, and a fourth group G4 including two first burners 16A. The arrangement order of the first burners 16A and the second burners 16B of the first group G1 in the circumferential direction is different from that of any of the second group G2 to the fourth group G4. The fuel ejector 14C of the third embodiment also has eight main burners 16 as in the first embodiment. That is, the number which can equally divide the plurality of main burners 16 in the circumferential direction is two or four.

According to the third embodiment described above, as in the first embodiment, the first burners 16A and the second burners 16B are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction centering on the combustor axis Ac.

Thus, the fuel ejector 14C can form a flame that is not uniform in the circumferential direction, without using a plurality of types of main burners having different outlines.

As a result, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burner 16.

Further, since the first burners 16A and the second burners 16B are not disposed in rotational symmetry, it is possible to suppress the flame from becoming uniform in the circumferential direction.

Furthermore, since the concentration center of the heat release rate of the flames due to main burners 16 as an index is shifted away from the combustor axis Ac that is the central position of arrangement of the plurality of main burners 16, it is possible to suppress the flame from becoming uniform, by breaking a balance of the flame in the circumferential direction.

In addition, by setting the arrangement pattern in the circumferential direction of the first burners 16A and the second burners 16B to an arrangement pattern in which the magnitude of the composite vector SV is equal to or greater than the magnitude of the unit vector UA (or UB), it is possible to suppress the flame from becoming uniform, by breaking a balance of the flame in the circumferential direction.

Furthermore, in a condition where the plurality of main burners 16 disposed at intervals in the circumferential direction are divided in the circumferential direction into groups each including one or some of the main burners 16 adjacent to each other in the circumferential direction and each groups includes the same number of the main burners 16, the arrangement relationship between the first burners 16A and the second burners 16B in at least one group is different from that of the other groups. Therefore, it is possible to suppress the flame from becoming uniform in the circumferential direction.

Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be described on the basis of the drawings. In the fourth embodiment, the arrangement pattern of the main burners is changed with respect to the first embodiment described above. The fourth embodiment differs from the first embodiment in that the magnitude of the composite vector is less than “1”. Therefore, the same parts as those of the first embodiment will be explained by being denoted by the same reference numerals, and the repeated explanation will not be provided.

As shown in FIG. 9, a fuel ejector 14D in the fourth embodiment is equipped with a first burner 16A and a second burner 16B as a plurality of main burners 16, as in the fuel ejector 14A of the first embodiment described above. The first burner 16A and the second burner 16B have the same configuration except that the circulating direction of the compressed air in the first burner 16A is opposite to the circulating direction of the compressed air in the second burner 16B.

In the fuel ejector 14D of the fourth embodiment, seven first burners 16A are disposed continuously in the circumferential direction, and one second burner 16B is disposed. That is, only one of the plurality of main burners 16 disposed in the circumferential direction is the second burner 16B, and all the others are the first burners 16A. The fuel ejector 14D shown in FIG. 9 shows a case in which eight main burners 16 are provided as in FIG. 4. However, the number of main burners 16 may be greater than 1, and may be, for example, nine or more, or seven or less.

The first burners 16A and the second burner 16B of the fuel ejector 14D are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction, as in the fuel ejector 14A.

Furthermore, the first burners 16A and the second burner 16B of the fuel ejector 14D are disposed in an asymmetric arrangement pattern (an arrangement pattern that is not rotationally symmetrical) in the circumferential direction centering on the combustor axis Ac.

Further, the concentration center of g of the heat release rate in the fuel ejector 14D is shifted away from the combustor axis Ac, as in the fuel ejector 14A of the first embodiment.

Furthermore, when two main burners 16 adjacent to each other in the circumferential direction are set as one group, four groups can be set in the circumferential direction in the fuel ejector 14D. In this case, when viewed in one direction (for example, clockwise) in the circumferential direction, it is possible to set a first group G1 including one second burner 16B and one first burner 16A (arrangement numbers “8” and “7” of the main burner 16), and a second group G2 to a fourth group G4 including two first burners 16A (arrangement numbers “6” and “5”, “4” and “3”, and “2” and “1” of the main burner 16). Further, the arrangement order of the first burners 16A and the second burners 16B of the first group G1 in the circumferential direction is different from that of any of the second group G2 to the fourth group G4. The fuel ejector 14D of the fourth embodiment also has eight main burners 16 as in the first embodiment. That is, the number which can equally divide the plurality of main burners 16 in the circumferential direction is two or four.

According to the fourth embodiment described above, as in the first embodiment, the first burner 16A and the second burner 16B are disposed in a non-periodic arrangement pattern over the entire circumference in the circumferential direction centering on the combustor axis Ac.

Thus, the fuel ejector 14D can form a flame that is not uniform in the circumferential direction, without using a plurality of types of main burners having different outlines.

As a result, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burner 16.

Further, since the first burners 16A and the second burners 16B are not disposed in rotational symmetry, it is possible to suppress the flame from becoming uniform in the circumferential direction.

Furthermore, the concentration center g of the heat release rate of the flames due to main burners 16 as an index is shifted away from the combustor axis Ac which is the central position of the arrangement of the plurality of main burners 16. Therefore, it is possible to suppress the flame from becoming uniform, by breaking a balance of the flame in the circumferential direction.

Furthermore, in a condition where the plurality of main burners 16 disposed at intervals in the circumferential direction are divided in the circumferential direction into groups each including one or some of the main burners 16 adjacent to each other in the circumferential direction and each groups includes the same number of the main burners 16, the arrangement relationship between the first burners 16A and the second burners 16B in at least one group is different from that of the other groups. Therefore, it is possible to suppress a flame from being uniformly formed in the circumferential direction.

EXAMPLE

Next, an example of a combustor having the fuel ejector of each embodiment described above will be described.

For the arrangement patterns in which the first burner 16A and the second burner 16B are disposed from Case 1 to Case 22 shown in the following table, the concentration center of the heat release rate and the magnitude of the composite vector are obtained, and the magnitude of the combustion instability is obtained. In the following table, the numbers “1” to “8” described at the top in each row correspond to the positions of the main burners 16 in the circumferential direction of each embodiment described above. A “reverse circulating number” described on the leftmost side in the following table is the number of second burners 16B in one fuel ejector. Further, a “concentration center of heat release rate” represents a distance from the combustor axis Ac to the concentration center. When securing the concentration center of the heat release rate, if the swirl directed to the radially outer side is strong, the heat release rate is set to 1.5, and if the swirl directed to the radially inner side is strong, the heat release rate is set to 0.5.

TABLE 1 Reverse Concentration circulating center of Heat number Case 1 2 3 4 5 6 7 8 release rate 0 0 0 0 0 0 0 0 0 0 0.0000 1 1 0 0 0 0 0 0 0 1 0.0478 2 2 0 0 0 0 0 0 1 1 0.0884 3 0 0 0 0 0 1 0 1 0.0676 4 0 0 0 0 1 0 0 1 0.0366 5 0 0 0 1 0 0 0 1 0.0000 3 6 0 0 0 0 0 1 1 1 0.1155 7 0 0 0 0 1 0 1 1 0.0829 8 0 0 0 0 1 1 0 1 0.0829 9 0 0 0 1 0 0 1 1 0.0478 10 0 0 0 1 0 1 0 1 0.0478 11 0 0 0 1 1 0 0 1 0.0478 12 0 0 1 0 0 1 0 1 0.0198 4 13 0 0 0 0 1 1 1 1 0.1250 14 0 0 0 1 0 1 1 1 0.0884 15 0 0 0 1 1 0 1 1 0.0676 16 0 0 0 1 1 1 0 1 0.0884 17 0 0 1 0 0 1 1 1 0.0676 18 0 0 1 0 1 0 1 1 0.0366 19 0 0 1 0 1 1 0 1 0.0518 20 0 0 1 1 0 0 1 1 0.0000 21 0 0 1 1 0 1 0 1 0.0366 22 0 1 0 1 0 1 0 1 0.0000

EXAMPLE

In this table, the arrangement of the main burner 16 in the fuel ejector 14A of the first embodiment described above is a case “6”. The arrangement of the main burner 16 in the fuel ejector 14B of the second embodiment is a case “2”. The arrangement of the main burner 16 in the fuel ejector 14C of the third embodiment is a case “13”. The arrangement of the main burner 16 in the fuel ejector 14D of the fourth embodiment is a case “1”.

In this table, when the first burner 16A is disposed, it is indicated by “0”, and when the second burner 16B is disposed, it is indicated by “1”.

COMPARATIVE EXAMPLE

In a case “0”, a case “5”, a case “20”, and a case “22” in the above table, the first burner 16A and the second burner 16B are disposed in a periodic arrangement pattern over the entire circumference in the circumferential direction, respectively.

(Concentration Center of Heat Release Rate)

The values of the concentration center of the heat release rate of each of the case “0”, the case “5”, the case “20” and the case “22”, which are comparative examples, are “0.0000”.

On the other hand, in all cases except the comparative example, the value of the concentration center of the heat release rate is larger than “0.0000”.

(Magnitude of Composite Vector)

In FIG. 10, a solid line represents the value of the concentration center of the heat release rate. In FIG. 10, broken lines represent the magnitude of the composite vector. In FIG. 10, a left end portion of a horizontal axis is a case “0”, and a right end portion thereof is a case “22”. That is, in the horizontal axis, the case number increases toward the right side. In FIG. 10, a thick solid line extending in the horizontal direction is an example of a reference value of the value of the concentration center of the heat release rate and the magnitude of the composite vector.

As shown in FIG. 10, it can be seen that the magnitude of the composite vector (broken lines) is correlated with the value of the concentration center of the heat release rate (solid line). The magnitude of the composite vector and the value of the concentration center of the heat release rate are particularly high numerical values in the cases “2”, “6” and “13” corresponding to the first, second and third embodiments described above. Although the values are the numerical values lower than of the cases “2”, “6”, and “13”, the magnitude of the composite vector and the value of the concentration center of the heat release rate are also values sufficiently higher than “0”, even in the case “1” corresponding to the fourth embodiment.

When the value of pressure fluctuation due to combustion instability is verified by simulation calculation, in the cases “1”, “2”, “6” and “13”, a tendency in which the combustion instability is reduced more than that in the case “0” was confirmed.

In each of the cases “1”, “2”, “6”, and “13”, the arrangement of the first burner 16A and the second burner 16B is not periodic and not rotationally symmetrical, and the value of the concentration center of the heat release rate and the magnitude of the composite vector is larger than those in the case “0”. In particular, in the cases “2” and “6”, the reduction of the combustion instability was remarkable.

That is, it was confirmed that there is a correlation between the non-periodicity of the arrangement pattern of the first burner 16A and the second burner 16B and the reduction of the combustion instability.

The present invention is not limited to the configurations of the above-described embodiments, and design changes can be made without departing from the scope of the invention.

For example, the present invention is not limited to the arrangement pattern of the first embodiment to the fourth embodiment. That is, the present invention is not limited to the arrangement pattern of cases “1”, “2”, “6” and “13”. In other cases (arrangement pattern) except the case “0”, the case “5”, the case “20” and the case “22”, an arrangement pattern other than case “1”, “2”, “6” and “13” may be used.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to a combustor and a gas turbine. According to the present disclosure, it is possible to suppress an occurrence of combustion instability, while suppressing an increase in man-hours involved in the manufacturing of the main burner.

REFERENCE SIGNS LIST

1 Gas turbine

2 Compressor

3 Combustor

4 Turbine

6 Compressor rotor

7 Compressor casing

8 Turbine rotor

9 Turbine casing

10 Gas turbine rotor

11 Gas turbine casing

13 Combustion cylinder

14A, 14B, 14C, 14D Fuel ejector

15 Pilot burner

16 Main burner

16A First burner

16B Second burner

17 Burner holding cylinder

18 Pilot nozzle

18 a Injection hole for fuel injection

19 Pilot burner cylinder

21 Main body

22 Cone portion

23 Main nozzle

23 a Injection hole for fuel injection

24 Main burner cylinder

25 Main Swirl

A Compressed air (primary air)

Ac Combustor axis

Ar Rotation axis

Da Axial direction

F Fuel

g Concentration center

G1 First group

G2 Second group

G3 Third group

G4 Fourth group

GEN Generator

SV Composite vector

UA Unit vector

UB Unit vector 

1. A combustor comprising: a plurality of first burners each adopted as a main burner circulating a primary air in one direction to generate an air-fuel mixture; and a plurality of second burner each adopted as the main burner circulating the primary air in the other direction opposite to the first burners to generate another air-fuel mixture, wherein the main burners are disposed at intervals in a circumferential direction the combustor, and the first and second burners are disposed in a non-periodic arrangement pattern over an entire circumference in the circumferential direction.
 2. The combustor according to claim 1, wherein the first and second burners are disposed in an asymmetric arrangement pattern in the circumferential direction.
 3. The combustor according to claim 1, wherein the first and second burners are disposed in an arrangement pattern in which a concentration center of heat release rate of all the plurality of main burners is shifted away from a central position in the circumferential direction.
 4. The combustor according to claim 1, wherein the first and second burners are disposed in an arrangement pattern in which a magnitude of a composite vector obtained by combining each of unit vectors according to a direction of a radial flow occurring at a boundary between the first and second burners in the circumferential direction is equal to or greater than magnitudes of the unit vectors.
 5. The combustor according to claim 1, wherein, in a condition where the plurality of main burners disposed at intervals in the circumferential direction are divided in the circumferential direction into groups each including one or some of the main burners adjacent to each other in the circumferential direction and each groups includes the same number of the main burners, an arrangement relationship between the first and second burners in at least one of the groups is different from other groups.
 6. A gas turbine comprising the combustor according to claim
 1. 